In watercraft, in particular engine-driven speedboats, drive concepts are often used in which a drive engine of the watercraft is arranged inside the latter and is actively connected, via a drive unit in the area of the boat's hull, to one or more propellers. For this purpose the drive unit usually passes through an opening in the hull or rear transom of the boat's hull. Thus, with such arrangements powerful engines, including also alternative drive concepts, can be used.
From DE 699 33 288 T2 a drive arrangement for an inboard-outboard drive is known, in which a drive unit with an upper part arranged in the area of an engine and in a hull of the watercraft, and a lower part, is provided. The lower part projects through an opening in the hull into the surrounding water and has at its end a propeller which, when it rotates, propels the watercraft forward. To produce this rotation a drivetrain extends through the upper and lower part of the drive unit, by means of which rotary movement of the engine can be transmitted to the propeller by shafts and bevel gear assemblies. In addition two seals, one behind the other, are provided in order to effectively prevent the entry of water through the opening in the hull. Furthermore, the upper part of the drive unit is connected at an end remote from the engine to a rubber mounting that acts on one side which, while the watercraft is being propelled forward, transfers tilting movements about the transverse axis into the hull and damps them.
However, this drive arrangement of the prior art has the considerable disadvantage that reaction forces and torques in all other directions are not taken up by the rubber mounting acting on one side, but have to be absorbed by an engine mounting and by the seals. Now, both when the watercraft is moving round a curve and when it is moving in reverse, such tilting movements of the drive unit take place. As a result the seal between the drive unit and the hull has to be made more rigid in order to be able to absorb the loads and vibrations over a long time without problems, but this at the same time adversely affects its sealing properties. Furthermore, an engine mounting has to be made substantially more robust.